android - Enable and disable dialog depending on correct input? -

this popup button needs disabled if user clicks submit without entering input first:

new alertdialog.builder(getactivity())     .setview(view)     .setpositivebutton(android.r.string.ok,             new dialoginterface.onclicklistener() {         @override         public void onclick(final dialoginterface dialog,                 final int which) {             edittext nameedittext = (edittext) view                     .findviewbyid(                             r.id.save_search_dialog_name);             posttobus(new savesearchevent(                     nameedittext.gettext().tostring(),                     search));             posttobus(new googleanalyticevent(                     ga.category_search_control,                     ga.event_search_save_search));             dialog.dismiss();         }         //check see if dialog empty         private boolean isempty(edittext ettext) {             return ettext.gettext().tostring().trim().length() == 0;         }     } 

i trying create method check ensure popup dialog cannot blank. have attempted method isempty , unsure how use it, or maybe isn't correct approach? assistance appreciated.

can provide context please? have button should enabled/disabled? in case case suggest using this:

edittext edittext = (edittext)findviewbyid(r.id.your_edit_text_id); edittext.addtextchangedlistener(new textwatcher() {      @override     public void aftertextchanged(editable s) {      }      @override     public void beforetextchanged(charsequence s, int start, int count, int after) {     }      @override     public void ontextchanged(charsequence s, int start, int before, int count) {         if(textutils.isempty(s)) { // check whatever want             // disable button or         } else {             // enable         }     }   });